Sound producer



Aug. 25 1931.

c. s. KELLEY v 1,820,143 scum) PRODUCER Filed May 16. 1930 1 l6 9 l7 8 l6 l0 7 INVE FOR B$ELJL SKELLEY ATTORNEY Patented Aug. 25, 1931 UNITED STATES PATENT oFFicE CECIL S. KELLEY, OF EAST MCKEESI'ORT, PENNSYLVANIA, ASSIGNOR TO THE .\VESTING- HOUSE AIR BRAKE COMPANY, OF WILMERDING, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA scum) PRODUCER Application filed May 16, 1930. Serial No. 453,005.

This invention relates to sound producing devices, and more particularly to the type employing a vibratory diaphragm.

An object of the invention is to provide an improved sound producer of the above type which is adapted to be operated by a partial vacuum.

Another object of the invention is to provide an improved sound producer of the character mentioned, which is simple in construction, and reliable and exact in function under all conditions of service.

The invention also comprises certain new and useful improvements in the construction,

arrangement and combination of the several parts of which it is composed, as will be hereinafter more fully described and claimed.

In the accompanying drawing, the single figure is a vertical longitudinal section of a sound producing device embodying the invention.

Referring to the drawing, the sound producer may comprise a casing 6, having a chamber 7, which is open to a flexible diaphragm 8, said diaphragm being clamped in position by a cover plate 9, which is secured to the casing by screws 10.

The casing 6 is provided with an opening 11 at the side opposite the diaphragm 8, into which is mounted an amplifying horn 12. Projecting inwardly of the casing 6 and con centrally disposed with respect to the opening 11, is an annular boss, which constitutes a resonance tube 13. The free end of the tube 13 just engages the diaphragm 8.

Secured to the central portion of the diaphragm 8 and extending into the open end of the tube 13 is a weight 14.

The chamber 7 is connected to a pipe 15, leading from a suitable source of partial vacuum, such as a reservoir or the intake manifold of an internal combustion engine, (not shown).

The diaphragm 8 is provided with a plurality of openings 16. These openings provide restricted ports from the chamber 7 to the chamber 17 on the opposite side of the diaphragm.

In operation, when it is desired to operate the device, the source of partial vacuum is connected to the chamber 7, through the pipe 15, and from the chamber 7 to the chamber 17, through the openings 16 in the diaphragm 8. With the reduction in fluid pressure in chamber 17, the atmospheric pressure against the face of the diaphragm 8 within the tube 13, forces the diaphragm away from the free edge of the tube 13, and thereby places the diaphragm under tension.

When the diaphragm 8 thus moves outwardly from the tube 13, communication is opened from the space within the tube 13 to the vacuum chamber 7, and since chamber 7 is in communication with chamber 17 through the openings 16, the pressure in chamber 17 tends to be built up. The fluid pressures on opposite sides of the diaphragm thus tend to balance or equalize, permitting the tension of the diaphragm to return the diaphragm to its seat. The opening movement is then repeated.

The diaphragm 8 is. thus caused to vibrate and thereby produces a sound which is amplified by the usual operation of the horn 12.

l/Vhile one illustrative embodiment of the invention has been described in detail, it is not my intention to limit its scope to that embodiment or otherwise than by the terms of the appended claims.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is: y

1. A sound producer comprising a chamber adapted to be connected to a source of partial vacuum, a flexible diaphragm subject on one side to atmospheric pressure and to the partial vacuum in said chamber, and a chamber on the other side of said diaphragm in com-- munication with the first named chamber.

2. A sound producer comprising chamber adapted to be connected to a source of partial vacuum, a flexible diaphragm subject on one side .to atmospheric pressure and to the partial vacuum in said chamber, a chamber on the other side of said diaphragm, and means by which the second chamber is connected with the first chamber.

In testimony whereof I have hereunto set my hand, this 9th day of May, 1930.

CECIL S. KELLEY. 

